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Idaho · THREADEX · 1875–2026

Boise, ID

43.567°N, 116.241°W · station BOIthr · 152 years of record
86°F
forecast high · Sep 1

7-Day Forecast

NWS NDFD forecast high temperature for Boise.
86°TUE9/178°WED9/271°THU9/373°FRI9/477°SAT9/579°SUN9/677°MON9/7

This Day in History

Every year's high on each of the next 7 forecast dates at Boise — toggle a day below. The forecast line shows where it lands; the ringed bar is the hottest on record.

Ranks

#65 / 151
warmest Sep 1 in 151 yrs of record

Warmest Sep 1 ever

102°F
set in 1945

Coolest Sep 1 ever

55°F
set in 1964
Forecast high 86°F — 65th warmest Sep 1 of 151 years · record 102°F (1945) · warmest since 2025.
1875: 80°F1876: 88°F1877: 78°F1878: 96°F1879: 86°F1880: 67°F1881: 67°F1882: 87°F1883: 77°F1884: 81°F1885: 84°F1886: 70°F1887: 71°F1888: 98°F1889: 70°F1890: 75°F1891: 89°F1892: 87°F1893: 92°F1894: 81°F1895: 85°F1896: 74°F1897: 72°F1898: 67°F1899: 80°F1900: 77°F1901: 83°F1902: 88°F1903: 89°F1904: 80°F1905: 84°F1906: 81°F1907: 75°F1908: 81°F1909: 82°F1910: 71°F1911: 93°F1912: 71°F1913: 75°F1914: 81°F1915: 81°F1916: 96°F1917: 88°F1918: 89°F1919: 81°F1920: 76°F1921: 83°F1922: 79°F1923: 90°F1924: 78°F1925: 88°F1926: 72°F1927: 76°F1928: 88°F1929: 81°F1930: 76°F1931: 85°F1932: 74°F1933: 80°F1934: 85°F1935: 85°F1936: 86°F1937: 79°F1938: 90°F1939: 74°F1940: 92°F1941: 72°F1942: 84°F1943: 83°F1944: 89°F1945: 102°F1946: 87°F1947: 90°F1948: 84°F1949: 93°F1950: 96°F1951: 79°F1952: 80°F1953: 82°F1954: 94°F1955: 91°F1956: 77°F1957: 80°F1958: 84°F1959: 75°F1960: 88°F1961: 73°F1962: 88°F1963: 82°F1964: 55°F1965: 81°F1966: 80°F1967: 98°F1968: 87°F1969: 92°F1970: 85°F1971: 85°F1972: 83°F1973: 71°F1974: 89°F1975: 70°F1976: 92°F1977: 77°F1978: 88°F1979: 90°F1980: 73°F1981: 85°F1982: 86°F1983: 79°F1984: 61°F1985: 76°F1986: 77°F1987: 101°F1988: 87°F1989: 89°F1990: 91°F1991: 87°F1992: 86°F1993: 85°F1994: 87°F1995: 94°F1996: 82°F1997: 97°F1998: 98°F1999: 73°F2000: 80°F2001: 92°F2002: 87°F2003: 88°F2004: 102°F2005: 87°F2006: 84°F2007: 96°F2008: 69°F2009: 95°F2010: 78°F2011: 77°F2012: 88°F2013: 94°F2014: 77°F2015: 87°F2016: 92°F2017: 93°F2018: 82°F2019: 97°F2020: 76°F2021: 80°F2022: 97°F2023: 85°F2024: 91°F2025: 101°F86° forecast556065707580859095100105188018901900191019201930194019501960197019801990200020102020
📖 Boise's full Climate Almanac →

The Numbers

Forecast high · Sep 186°F
Hottest this date since2025
This-date record102°F
This-date rank#65 of 151
Hottest at any time since2026
All-time record111°F (1898)
Odds to tie/break0.0% (daily)
Period of record1875–2026

Record Book

The hottest and coldest ever recorded at Boise in each calendar month, and for the whole 1875–2026 record — with the year each was set.
MonthRecord HighRecord Low
Jan66°FJan 31, 2024-28°FJan 16, 1888
Feb71°FFeb 29, 1992-15°FFeb 5, 1989
Mar83°FMar 20, 20265°FMar 13, 1906
Apr92°FApr 26, 189811°FApr 1, 1936
May100°FMay 29, 189722°FMay 5, 1982
Jun110°FJun 28, 201530°FJun 5, 1901
Jul111°FJul 12, 189835°FJul 5, 1986
Aug110°FAug 4, 196132°FAug 25, 1892
Sep104°FSep 7, 202223°FSep 24, 1926
Oct94°FOct 1, 199211°FOct 29, 1971
Nov78°FNov 6, 1999-10°FNov 28, 1896
Dec70°FDec 10, 1939-25°FDec 22, 1990
All-time111°FJul 12, 1898-28°FJan 16, 1888

2026 Records So Far

Records set or tied at Boise so far this year — through Aug 30.

Record Highs in 2026

4 broke
plus 3 tied — daily record highs set this year
Monthly high record this year: Mar (83°F)

Record Lows in 2026

0 broke
plus 0 tied — daily record lows set this year

Record Warm Nights & Cold Days

Two more daily records, kept separate from the rankings: the warmest a night has ever stayed (record high minimum) and the coldest a day has ever gotten (record low maximum) — the flip side of the usual record high and low.

Warmest low ever

83°F
record high minimum — the night it never cooled · Jul 25, 1891

Coldest high ever

-10°F
record low maximum — the day it never warmed · Jan 15, 1888
MonthWarmest lowColdest high
Jan49°FJan 13, 1969-10°FJan 15, 1888
Feb51°FFeb 10, 19613°FFeb 9, 1933
Mar58°FMar 26, 189524°FMar 15, 1906
Apr70°FApr 28, 193935°FApr 1, 1936
May71°FMay 31, 190342°FMay 2, 1964
Jun81°FJun 30, 189248°FJun 10, 1892
Jul83°FJul 25, 189157°FJul 3, 1902
Aug79°FAug 7, 188155°FAug 31, 1964
Sep76°FSep 5, 199848°FSep 24, 1934
Oct67°FOct 3, 196330°FOct 30, 1935
Nov56°FNov 14, 19069°FNov 15, 1955
Dec55°FDec 14, 1929-6°FDec 22, 1990
All-time83°FJul 25, 1891-10°FJan 15, 1888

Hot Streaks

Current run

0 days
consecutive days with a high ≥ 90°F

Longest ever

50 days
record run, ended Aug 22 1875

So far in 2026

58 days
days with a high ≥ 90°F this year

Climate Normals

Normal high & low by month, from Boise's own 1991–2020 record. Today's normal high: 86°F · forecast is +0° vs normal.
Jan: 39°FJan: 25°FFeb: 46°FFeb: 29°FMar: 56°FMar: 34°FApr: 62°FApr: 39°FMay: 72°FMay: 47°FJun: 81°FJun: 54°FJul: 93°FJul: 62°FAug: 91°FAug: 61°FSep: 80°FSep: 52°FOct: 65°FOct: 41°FNov: 49°FNov: 31°FDec: 39°FDec: 25°FJFMAMJJASOND

Sun & Location

Sun & Daylight Today

Sunrise5:08 AM
Sunset6:21 PM
Solar noon11:45 AM
Daylight13h 12m · losing 20 min/wk
Local standard time (no DST), level horizon.

Location

43.57°N, 116.24°W

Nearby Stations

Ontario, OR49 mi NWStanley, ID77 mi NEMcCall, ID91 mi NJerome, ID107 mi SEBaker City, OR117 mi NWChallis, ID120 mi NE

The Last 6 Weeks

Boise's observed daily high for the last six weeks — a white ring marks any day that broke or tied its daily record for that date.
Boise, ID — last six weeks of daily high

2026 So Far

Every day this year against Boise's own record — the record high, the normal, and the full span ever seen. A shareable look at where the year stands.
Boise, ID — 2026 daily high trace
Download year chart

Every Day Since 1875

Each cell is one day's high at Boise, coloured by temperature — 152 years of record, so heat waves read as warm streaks and cold snaps as blue.
Boise, ID daily high heat map 1875–2026

Days Above the Mark

How many days a year hit a given high at Boise — counted through Sep 1 each year, so you can see whether 2026 is running hot. Pick a threshold:
58 days ≥90°F so far in 2026 — tied for the 13th most in 152 years. Normal for this point: 42. Record: 71 in 2013.

Share Card

A ready-to-share summary of Boise's outlook — post it, or link this page.
Boise, ID hot share card
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